1. Field of the Invention
The present invention relates to an improved impact wrench structure, and particularly, to an impact wrench carried in an automobile, in case there occurres a flat tire on the way, it can be operated to detach the punctured tire and replace it with a spare one by tightening/loosening various kinds of screw-like fixing parts using power supply from the automobile battery.
2. Description of the prior art
At present, most of the impact wrench for replacing a flat tire by tightening/loosening various kinds of screw-like fixing parts have almost resembling functions but with different internal structures. For example, "Innovated structure for impact wrench" disclosed by U.S. Pat. No. 322,853, Taiwan ROC. In this case, when replacing a flat tire, tightening/loosening screw-like fixing parts is performed by a centrifugal force transferred from a motor as a power source. However, due to a lot of parts are involved, it has to spend much more time to accomplish the assembly work with the result of increasing the manufacturing cost, moreover, some fixing parts having mutually different size or shape become an obstacle to applicability and increase fault rate of the wrench according to this invention.
Another cited case, "structure for impact wrench" disclosed in U.S. Pat. No. 326,735 Iaiwan ROC is an invention made to eleminate shortcomings of the former case described above. In the latter case, a clutch plate which is included in the former case is omitted and the figure and features of the hammer are changed and improved, but it is still unable to thoroughly eliminate the rest of shortcomings inherent to the former cited case.
In order to overcome the shortcomings inherent to the conventional techniques of the impact wrench including the cited cases described above, the present inventor has delved into this matter with a long time efforts and came to realization of the present invention.